There was a Public Service Commissioner in the Travancore state whose duty was to select candidates for direct recruitment to various categories of posts under the Government. G.D. Nokes was appointed as the first Public Service Commissioner on 14th June, 1936. The Office of the Public Service Commissioner, Travancore continued to function till the integration of Travancore and Cochin States.

In Cochin there was a Staff Selection Board constituted in 1936 to select candidates for initial recruitment to lower posts. In 1947 a three member Cochin Public Service Commission was constituted under an Act of the State Legislature.

The Travancore-Cochin State was formed on 1st July, 1949 by the integration of the two Princely States of Travancore and Cochin.With the integration of the States of Travancore and Cochin on 1st July, 1949 a Public Service Commission for the State of Travancore-Cochin was constituted by an Ordinance. There were three members on the Commission including the Chairman. The functions of the Travancore-Cochin Public Service Commission were generally the same as those laid down in the Government of India Act, 1935. Later, when the Constitution of India came into force on the 26th January, 1950, the Travancore-Cochin Public Service Commission continued to function under the Constitutional Provisions.

The State of Kerala was formed on 1st November 1956 consequent on the Reorganisation of States. It comprises the former Travancore-Cochin State (except the present Kanyakumari District and Shencottah Taluk of the present Tamil Nadu) and the Malabar District and the Kasargod Taluk of South Kanara District of the then composite Madras State.

With the formation of the State of Kerala on 1st November 1956 as a result of the reorganisation of States, the Travancore-Cochin Public Service Commission was transformed into the Kerala Public Service Commission. The number of the Members of the Commission was increased to Five in 1959, to Seven in 1971, to Eight in 1981, to Nine in 1982, to Thirteen in 1983, to Fourteen in 1984 , to Fifteen in 1984 and to the present strength of Eighteen in 2005.